A number of plot points will inevitably be revealed in the course of these writings. My intent is to review this program from the perspective of the Doomer / Prepper / Survivalist community, but, to do that effectively, some things have to be explained in greater detail than I might normally prefer in a review. As a result, spoilers will follow. You have been warned.
The premiere of season 3 picks up our group of survivors several months after where we last left them. In fact, the Winter has passed, and we are to understand that they have spent the ensuing months moving from deserted location to deserted location, scavenging for food, fuel, and supplies along the way. We see a designated fire-team (including young Carl, who has become a good gun-hand) move quietly room-to-room to clear a house of Walkers, while the others wait outside. Lori, by the way, is very, very pregnant now, apparently near full-term.
At some point, someone has rigged some sort of homemade suppressors for their handguns, which will undoubtedly help with the fact that, up until now, shooting one Walker carried the risk of attracting hundreds more. Not sure how they managed to make the suppressors, as they appear to be machine-cut metal, or from where in the world they might have found to scavenge such items. Perhaps that will be addressed in later episodes. Rick's, in particular, looks to be made from the body of a Maglite flashlight! Needless to say, I had never heard of such a thing, so I Googled it; apparently, it is possible -- expect a dedicated article about that little tidbit tomorrow! The other suppressor shown looks like it might have been made by sawing off the handle of a mini-aluminum baseball bat and machining a borehole down the center, which, I'm thinking, is likely more Hollywood prop department fantasy than it is real-life utility, especially in the middle of a zombie apocalypse -- I'm not sure how they could have made it or if it even would work, but it does look pretty cool. As for the rest of the group's weapons, most seem to have become very proficient with manual weapons, such as sharpened garden implements and fireplace pokers and the like. Daryl, of course, is still a bad@$$ with his hunting crossbow.
Once the site is cleared, the rest of the group is drawn inside via signal, everyone careful to keep very quiet. Obviously, they're in a pretty bad way, all in all. This is evidenced by the fact that Carl is set to open one of two cans of dog food he found (the only food in the house) and eat it, before his father takes it away from him, plainly very frustrated over his inability to provide better for everyone. Daryl also shoots an owl (not typically a game bird), which is found roosting in an upstairs bedroom -- further evidence that the group is struggling for food sources. They're also seen eating what look like ketchup packets. In the end, their rest is a short one. Walkers soon converge on the house, forcing them to retreat out the backdoor, but not before Maggie scavenges an ax from the house's environs; they've obviously gotten pretty good at recognizing what items could be an asset.
In my opinion, they should have eaten the dog food. It isn't made from the best quality meats (lower quality than human grade anyway), but it is a source of protein and is edible by people with no ill health effects, other than perhaps being unpalatable. I would have cooked the owl, cut it up into little pieces, and made a stew out of it, the three cans of dog food, and whatever wild edibles might be about. Or, rather, I would have stuck them in my backpack to do what I just described at a later time, whenever we could find a secure enough place to build a fire.
Later, they halt their convoy on the road for 15 minutes in order to look at a map of the area and plan their next move. Rick assigns Carl as the point-man, on guard at the front of the column during their break, and it's obvious that having a job to do and being treated as something more than a little kid agrees with Carl. In fact, the group's security protocols seem well laid-out in general; even as Carl is on point, Hershel's youngest daughter Beth (who, I swear, they seem now to referring to as Betsy for some reason) watches the rear, armed with an axe.
They've apparently been zig-zagging around the area all Winter in an effort to avoid increasingly large, roving herds of Walkers, who are now boxing them in. Again, Rick echoes his position from the finale of last season that they cannot keep jumping from house-to-house and need, instead, to find a place to hole-up, though this time he's speaking more in regards to a place where they can spend a few weeks until the baby comes. Hershel is intent that Lori won't be able to take too much more of their hopping around in her condition. They plan to double-back, then push West. First, though, many go to refill their water jugs from a nearby creek (saying that they'll boil it later), as Rick and Daryl look for any wild game that might be around.
It is as they hunt that they discover the prison we saw in the final seconds of the season 2 finale.
It is infested with Walkers that can be seen milling aimlessly in its enclosed yard, but the chain-link fence walls and gates topped with barbed-wire and the observation towers are all intact, and Rick has the forward-thinking vision to see that it just might represent precisely the kind of place he has been looking for and preaching to the others that they needed to find. They cut through the chain-link to gain entrance to the area between the outer- and inner-walls, resealing the breach behind themselves with wire. I guess it's a good thing that Walkers are dumb as stumps and not exactly the types to be untying knots. Running around to the inner-gate, the plan is to close the main-gate of the prison itself, preventing any more of the Walkers from up there from filling the yard; then, they need only pick-off the ones already in the yard and they will have gained for themselves a secure field in which to camp long-term.
Glenn volunteers to me the one to run through the infested yard to close the gate, saying he's the fastest, but Rick has other ideas. He assigns Glenn, Maggie, T-Dog, and Beth to make a racket and draw as many Walkers as possible over away from the main avenue, and to kill as many as they can through the fence from the safety of the other side (between the inner- and outer-fences). Daryl, Carol (who Rick says is becoming a petty good shot), Carl, and Hershel are to climb the three accessible towers to cover Rick as he, himself, runs for the gate. Again, we see Rick being a good leader, both in his decisiveness, planning, and his willingness to accept the most dangerous parts of their activities for himself to complete. There is a concern that the group is low on ammo, and so Carol, especially, is told to take her time and choose her shots wisely. In the end, the plan works well and the group gains control of the secure prison yard, the first time they've had so much safe space since leaving the farm.
That night, around the fire, plans are made to gather the bodies (and, presumably, burn them) and possibly dig a canal under the fence to bring fresh water in from a nearby small lake; and Hershel comments that the soil is rich -- if they can get some seeds, he envisions they'll have no trouble growing tomatoes, cucumbers, and soybeans there. Meanwhile, Rick obsessively walks the perimeter over and over, making sure the barrier isn't compromised in any way.
Those who doubted Rick's leadership before now seem to be bought-in, saying that he has kept them safe longer than Shane likely would have been able. Tension remains, however, in the marriage of Lori and Rick, who insists his wife should eat part of the ration set aside for him (even though she protests), and, yet, will barely even speak to her (and, when they do talk at all, it is terse). Rick insists they all turn in early and then lays out for them his plans for one more deep push the next day into the prison itself. Noticing that most of the Walkers they've seen were dressed as either prisoners or guards, he surmises that the prison might have fallen to the plague early, leaving its supplies intact (including the infirmary, commissary, and at least the location of and means with which to access the facility's off-site armory). It will have to be hand-to-hand, as they are dangerously low on ammunition.
Next, the story moves away from the main group, and we see an impressive woman clear a small neighborhood store of Walkers using a Japanese katana sword. This is the previously hooded figure who saved Andrea in the season 2 finale. She loots the store of a few packets of aspirin, and we soon learn that her name is Michonne and the meds are for a very sick Andrea whom Michonne has left sheltered inside an old (non-working, of course) meat-locker.
Back at the prison, Rick, T-Dog, Daryl, Glenn, and Maggie venture into the prison's main-gate, moving in-unison and back-to-back, as the others repeat the distraction maneuver from the day before and kill Walkers through the fence from the safe side. Soon, they encounter Walkers who were once guards, dressed in full riot gear, making them considerably more difficult to kill, but they manage to prevail and soon clear-out an empty cell-block with actual beds in which to shelter. In the meantime, however, Daryl notices that some of these new batch of Walkers they have encountered were dressed as civilians, thus possibly casting doubt on Rick's earlier hopes.
Elsewhere, the fevered Andrea urges Michonne to leave her behind and save herself, but Michonne refuses. The place where they are holed-up is a little storefront that used to cold-store hunter's deer carcasses for them and butcher the meat, and it is surrounded by Walkers who apparently have not come in because Michonne has her two pet Walkers chained-up inside the entrance. I recall a scene from season 1 where someone chopped-up a Walker body and covered themselves in gore, so that they could pass among Walkers unnoticed; I think Michonne may have stumbled across this same phenomenon, which would explain why she drags two of them around with her that have been relieved of their arms (no scratching) and lower jaws (no biting), rendering them unable to harm her. The two women and the pet Walkers eventually leave together, sick or not, because Andrea fears that, if they stay, she'll die there.
Back at the prison, the main group has settle into the cleared cell-block a bit. Carl has apparently developed something of a crush on the young, yet still far older than him, Beth/Betsy, and Lori is experiencing anxiety over her pregnancy. She hasn't felt the baby move in awhile and fears she's lost it, her mind going to terrifying scenarios where, if everyone is infected, then the baby might become a Walker and tear her apart from the inside. Hershel tries to calm her down, but she makes him promise that, if the baby lives and she dies in childbirth or if she and the baby are both Walkers,he won't hesitate or try to save them, thus putting others at risk. She wants to be put down immediately in such a scenario, and she's also torn-up by the fact that Rick and Carl both hate her for putting Rick and Shane at odds.
Later on, a group comprised of Rick, Daryl, T-Dog, Glenn, Maggie, and Hershel go on a scouting mission to other parts of the prison, leaving an initially-disappointed Carl behind as a last defense for the others, in case the worst should happen. This is a kid who is at his best when trusted with responsibility, even if it is just a means of keeping him away from the more dangerous activities. The party explores through the darkened interior of the areas beyond their relatively secure cell-block, marking their way back with spray-painted arrows on the walls (ingenious!). They continue on until any further progress is blocked by them rounding a corner and coming face-to-face with a large cluster of Walkers.
In the ensuing flight back to safety, Glenn and Maggie get separated from the others. As the group back-tracks to try to locate them, Hershel gets bitten on the leg by a Walker that he believed to already be dead. Rick, in an effort to save his life (remember, everyone may be infected, but Walker bites and even scratches cause fever and death), chops off the wounded limb with a hatchet, hoping to stave off infection. Hershel loses consciousness from pain and blood loss as everyone tries to find a way to staunch the bleeding, and, just then, Daryl looks up and sees other survivors, alive within the prison, watching them and, apparently, equally surprised to see them.